Page 17 of 4770
3
CAMRY ± NEW FEATURES
167CN20
N.m (ft-lbf)
200
180
160
140
120140
130
120
110
100
90
1000 20003000 4000 5000 6000(HP) kW
130
120
110
100
90
80
70
60
50
40
30
20
10
0100
90
80
70
60
50
40
30
20
10
0
Torque
Output
Engine Speed (rpm)37
Performance Curve
Page 18 of 4770

CAMRY ± NEW FEATURES 38
2. Features of 5S-FNE Engine
Features of the 5S-FNE engine are listed below.
Item
Features
Performance
High compression ratio is used.
High lift camshaft is used.
Low back pressure muffler is used.
Fuel Economy
High compression ratio is used.
Valve spring load has been reduced.
Low-friction. TiN (titanium nitride) coated valve lifters has been adopted.
Low Emission
A fuel injection system containing gas injectors has been adopted.
Because the fuel is in the gaseous state, it does not come in contact with
the wall surface, making optimal air-fuel ratio control possible
immediately after the engine has been started.
Precision air-fuel ratio feedback control that uses an air-fuel ratio sensor
and a heated oxygen sensor has been adopted.
Two catalytic converters designed exclusively for the natural gas engine
have been adopted: the WU-TWC (Warm Up Three-Way Catalytic
Converter) and the TWC (Three-Way Catalytic Converter).
Other Features
Highly rigid pistons have been adopted to accommodate the high
compression ratio.
A CNG (Compressed Natural Gas) pressure regulator that precisely
regulates the CNG has been adopted.
A large-bore delivery pipe and fuel hose with minimal internal conduit
resistance have been adopted.
The electro magnetic fuel shutoff valve is added on the delivery pipe.
A fuel pressure sensor that corrects the fuel injection volume and a fuel
temperature sensor have been provided on the delivery pipe.
The starting performance of the engine at low temperatures has been
ensured by increasing the volume of the airflow of the IAC (Idle Air
Control).
Materials that excel in wear resistance have been adopted on the valves
and valve seats for both the intake and exhaust.
Rust-resistant spark plugs have been adopted.
Aluminum lining and carbon fiber have been adopted in the fuel tank.
For the fuel gauge, a fuel tank fuel temperature sensor and a fuel pipe fuel
pressure sensor have been adopted.
Page 19 of 4770
3
CAMRY ± NEW FEATURES
167CN03 167CN02
5S-FNE Engine 5S-FE Engine39
3. Engine Proper
General
The cylinder head and the pistons have been changed for the CNG application.
Cylinder Head
Materials that excel in wear resistance have been adopted on the valve seats for both the intake and exhaust.
The shape of the holes into which the injectors mount has been changed to accommodate the injectors de-
signed exclusively for the CNG application.
The shape of water jacket around plug has been modified to prevent the deformation.
Piston
To achieve a high compression ratio, the shape of the top of the piston has been changed and pin boss hole
with taper has been adopted.
An additional surface treatment has been provided to improve heat resistance.
The material has been changed to increase rigidity.
Page 20 of 4770

CAMRY ± NEW FEATURES
167CN04
Valve Lifters
Intake ValveAdjusting Shims
Exhaust Valve 40
4. Valve Mechanism
Camshaft
To recover the reduction of engine performance, the intake valve timing and the amount of lift of the intake
and exhaust valves have been changed from those of the base 5S-FE engine.
Specificaitons
Valve TimingValve Lift mm (in.)
EngineIntakeExhaustIntakeExhaustg
OpenCloseOpenCloseIntakeExhaust
5S-FNE3 BTDC38 ABDC45 BBDC3 AT D C7.9 (0.311)8.25 (0.325)
5S-FE43 ABDC7.7 (0.303)7.7 (0.303)
Intake and Exhaust Valves
To improve their wear resistance, the intake valves have undergone special heat treatment, and the mate-
rial of the exhaust vavles has been changed.
The shape of the stem to which the keepers attach has been changed to accommodate the adoption of the
cam with a high lift and of the inner shim type valve adjusting shims.
Valve Lifter and Adjusting Shims
TiN (titanium nitride) coated valve lifter is used to reduce the friction.
To accommodate the high lift, inner shim type valve adjusting shims are used.
Valve Spring
The valve springs for both the intake and exhaust sides accommodate the adoption of the cam with a high
lift and of the inner shim type valve adjusting shims. In addition, their spring rate has been optimized to
reduce friction.
Page 21 of 4770

3
CAMRY ± NEW FEATURES
167CN05
WU-TWC
167CN06
TWCSub MufflerMain Muffler41
5. Intake and Exhaust System
Throttle Body
The throttle body is basically the same as that of the 5S-FE engine. However, to ensure the starting perfor-
mance at low temperatures, the air passage for the IAC (Idle Air Control) has been increased on the 5S-FNE
engine. The IAC valve is a 1-coil type with a built-in driver.
Exhaust Manifold
As in the California specification 5S-FE engine,
the stainless steel exhaust manifold and WU-
TWC (Warm Up Three-Way Catalytic Convert-
er) have been integrated to improve the warm-up
performance of TWC, thus reducing exhaust
emissions.
However, the 5S-FNE engine uses a catalytic
converter that has been designed exclusively for
the CNG application, in which the loading of the
noble metal has been increased.
Exhaust Pipe
1) General
To secure sufficient luggage compartment capacity, the main muffler has been relocated below the rear
seat. Furthermore, the muffler capacity has been increased.
A 2-way exhaust control system has been adopted to improve engine performance and reduce the exhaust
noise.
Similar to the WU-TWC, the TWC (Three-Way Catalytic Converter) has been designed exclusively for
the CNG application, in which the loading of the noble metal has been increased.
Page 22 of 4770
CAMRY ± NEW FEATURES
167CN07
Exhaust Gas
Control Valve
Control Valve: Low Engine Speed
: High Engine Speed
42
2) 2-Way Exhaust Control System
a. General
A 2-way exhaust control system reduces the back pressure by opening and closing two control valves
that are enclosed in the main muffler, thus verying the exhaust gas passage.
The valves open steplessly in accordance with the operating condition of the engine, thus enabling
a quieter operation at low engine speeds, and reducing back pressure at high engine speeds.
b. Operation
The control valves are closed at low engine speeds because the pressure in the main muffler is low.
Therefore, the exhaust gas flows as indicated by the black arrow below, thus reducing the exhaust noise.
The control valves open at high engine speeds because the exhaust gas pressure increased. Therefore,
the exhaust gas flows as indicated by the white arrow below to reduce the back pressure, thus improving
the engine's power output.
Page 23 of 4770

3
CAMRY ± NEW FEATURES
172CM14
Fuel
Pressure
SensorFuel Temp.
SensorFuel
Pressure
RegulatorFuel Shutoff ValveFuel Tank
Fuel Shutoff ValveRelief Valve
Inlet Check
Valve
Fuel Temp.
Sensor
Coupler
Tank Valve Assembly
Vent Tube Manual
Shutoff
Valve Oil
Separator
Fuel Shutoff Valve Injectors
Delivery Pipe Discharge
ValveFuel
Pressure
SensorFuel
Filter43
6. Fuel System
General
The compressed gas [maximum pressure approximately 250 kg / cm
2 (3600 psi, 24.8 MPa) @ 21C
(70F)] from the CNG fuel tank located in the rear section of the vehicle is routed via a fuel filter to the
engine compartment. The pressure of the fuel is then reduced to 8 kg / cm
2 (114 psi, 785 kPa).
A pressure regulator and injectors designed exclusively for CNG application have been adopted.
A fuel pressure sensor and a fuel temperature sensor that are used for the correction of the fuel injection
volume are located on the delivery pipe.
The fuel tank, pressure regulator, and the delivery pipe are provided with shutoff valves that shut off the
fuel when the ignition switch is turned OFF.
In addition, these valves shut off the fuel when the engine stalls, the SRS airbag is deployed, or the pres-
sure in the main pipe becomes abnormally low.
A fuel temperature sensor for the fuel gauge is mounted on the tank valve assembly, and a fuel pressure
sensor is mounted immediately upstream of the pressure regulator.
Fuel System Diagram
Page 24 of 4770
CAMRY ± NEW FEATURES
167CN08
Tank Valve
AssemblyTank Band
Coil Springs
167CN26
Tank Valve AssemblyFuel
Temperature
Sensor 44
Fuel Tank
A fuel tank made with carbon fiber and alumi-
num lining has been adopted to prevent weight
increase.
Because the fuel tank expands along with the
increase in the pressure of the compressed gas,
the tank bands contain coil springs to accom-
modate the fluctuation in the perimeter of the
tank.
The fuel tank is provided with a tank valve as-
sembly.
Tank Valve Assembly
1) General
The tank valve assembly is mounted on the
tank and consists of a fuel shutoff valve, inlet
check valve, relief valve and two manual cut-
off valves.